Many structures are built using concrete, including, for instance, buildings, parking structures, apartments, condominiums, hotels, mixed-use structures, casinos, hospitals, medical buildings, government buildings, research/academic institutions, industrial buildings, malls, roads, bridges, pavement, tanks, reservoirs, silos, sports courts, and other structures.
Prestressed concrete is structural concrete in which internal stresses are introduced to reduce potential tensile stresses in the concrete resulting from applied loads; prestressing may be accomplished by post-tensioned prestressing or pre-tensioned prestressing. In post-tensioned prestressing, a tension member is tensioned after the concrete has attained a desired strength by use of a post-tensioning tendon. The post-tensioning tendon may include for example and without limitation, anchor assemblies, the tension member, and sheathes. Traditionally, a tension member is constructed of a material that can be elongated and may be a single or a multi-strand cable. Typically, the tension member may be formed from a metal or composite material, such as reinforced steel. The post-tensioning tendon conventionally includes an anchor assembly at each end. The post-tensioning tendon is fixedly coupled to a fixed anchor assembly positioned at one end of the post-tensioning tendon, the “fixed-end”, and stressed at the stressed anchor assembly positioned at the opposite end of the post-tensioning tendon, the “stressing-end” of the post-tensioning tendon.
A pocket former may be used to prevent or restrict concrete from filling in the area between the stressing-end anchor and the concrete form used to form the concrete member to allow access to the stressing-end of the tendon once the concrete member is poured. As understood in the art, the concrete form is a form or mold into which concrete is poured or otherwise introduced to give shape to the concrete member as it sets or hardens, thus forming the concrete member. Once the concrete has sufficiently hardened and the concrete form is removed, the pocket former is removed from the concrete member. In certain conventional uses, pocket formers are frustoconical in shape to facilitate removal from the concrete member. Conventionally, once the tendon is stressed, the pocket formed by the pocket former is filled with a material such as a cementitious grout or concrete to, for example, provide fire protection and corrosion protection.